Rant about forsale cars and rust

From my understanding and what I've seen adds mean when saying "Rust Free" is not that it doesn't have ANY rust but that is has no Cancerous problematic rust, just easily repairable Surface Rust.

So why do people use that term?

The dart Tara and I bought was "rust free" and I ended up putting 5 patch panels in. I knew it wasn't rust free so I wasn't disappointing but surface rust is still rust.